Dr. Smith proposes an interesting hypothesis. In AIM 1 she plans to determine whether excess levels of homocysteine and glutamate damage retinal ganglion cells in vitro and in vivo and whether this damage can be blocked by NMDA receptor antagonists and by sigma receptor ligand. IN AIM 2 she will determine whether sigma receptor ligands have a protective effect against the retinal ganglion cells death observed in early stages of diabetes. Finally in AIM 3, the investigator will use various methods to confirm the presence of type 1 sigma ligand in the retina. The investigator will analyze the pattern of type 1 sigma receptor expression in the retina.